SYT4 and obesity due to melanocortin 4 receptor deficiency: Based on our novel finding (overexpression of SYT4 in AT-T2D) and intriguing finding by Zhang et al. [52], we hypothesize that SYT4 can be used as a new biomarker for obesity and T2D and may be considered as prognostic marker for age-induced T2D, and negative regulation of SYT4 could potentially repair or reduce the degree of DNs.